7. Hand and Wrist MCQs

DISCUSSION: The lesion lies in zone II of the ulnar tunnel. In that zone the deep motor branch of the ulnar nerve is susceptible to compression. Distal to the hook of the hamate, the motor branch of the ulnar nerve dives deep to innervate the interossei as it begins to move from an ulnar to radial direction. Because of its course, it has little or no give in response to a mass effect from the floor of Guyon’s canal. Ganglions are the most common cause of ulnar nerve entrapment in the wrist. Lesions in zone I can affect both sensory and motor aspects of the ulnar nerve as well as the motor innervation of the hypothenar muscles. Lesions at the elbow or mid-to-proximal forearm are associated with dorsal hand numbness and tingling.

Patients with diabetes mellitus are prone to infection, and surgical treatment of their infections frequently requires multiple procedures. The triad of poor wound healing, chronic neuropathy, and vascular disease contributes to the increased infection rate. Studies have demonstrated increased amputation rates in patients with diabetes mellitus who have renal failure or deep polymicrobial or gram-negative infections.

There are no significant benefits demonstrated with formal physical therapy following distal radius fracture ORIF compared to a patient-guided home exercise program. Studies have shown no difference in grip strength, range of motion, or functional outcomes (such as DASH scores) between patients who undergo formal physical therapy and those who follow a home exercise program.

Disruption of the central slip of the extensor tendon at the PIP joint with volar migration of the lateral bands will result in the so-called boutonniere deformity, which includes loss of extension at the PIP joint and compensatory hyperextension at the DIP joint. The lesion is most often secondary to closed blunt trauma with acute forceful flexion at the PIP joint. This produces avulsion of the central slip from its insertion on the dorsal base of the middle phalanx with or without fracture and/or laceration of the extensor tendon at its insertion. In closed injuries the characteristic boutonniere deformity may not be apparent at the time of injury and may not be noted until 10 to 21 days after injury. Two diagnostic tests that are useful in early recognition of this lesion are: (1) a 15 deg to 20 deg or greater loss of active extension of the PIP joint when the wrist and MP joint are fully flexed and (2) extravasation of intraarticular radiopaque dye dorsal and distal to the PIP joint. Weak extension against resistance has also been noted to be a helpful diagnostic finding. Treatment in acute cases before fixed contractures have occurred may be achieved by progressively splinting the PIP joint into full extension and at the same time performing active and passive flexion exercises of the DIP joint. In a closed boutonniere deformity operative intervention is indicated under two circumstances. (1) when the central slip has been avulsed with a bone fragment which is lying free over the PIP joint and (2) a long-standing boutonniere deformity in a young person.

DISCUSSION: The development of arthritis in SLAC wrist follows a consistent pattern. Beginning at the radial styloid to the scaphoid articulation, it progresses through the entire radioscaphoid joint and the midcarpal joint. In all stages, the radiolunate joint is spared, which is the basis for a scaphoid excision and four-corner fusion performed as a motion-sparing procedure for treatment of this condition. REFERENCES: Wyrick JD: Proximal row carpectomy and intercarpal arthrodesis for the management of arthritis. J Am Acad Orthop Surg 2003;11:277-281. Watson HK, Ballett FL: The SLAC wrist: Scapholunate advanced collapse pattern of degenerative arthritis. J Hand Surg Am 1984;9:358-365. Watson HK, Ryu J: Evolution of arthritis of the wrist. Clin Orthop 1986;202:57-67.

Functional recovery after nerve injury-The outcome of peripheral nerve injuries is quite variable. Variables hypothesized to have an important role in determining the outcome of nerve repair include: (1) the age of the patient; (2) the type of nerve injured; (3) the distance the regenerating axons must grow to reach the target organ; (4) the length of the injured zone; (5) the timing of the nerve repair; (6) the status of the target organ at the time it is reinnervated; and (7) the technical excellence of the surgeon.Functional recovery is generally complete after a crush injury because the basement membrane and endoneurium are left intact, and the damaged axons can regenerate within their original endoneurial tubes and reinnervate their original target organ. After a complete lesion to the nerve, however, functional recovery of movement is often quite poor. The loss of functional recovery probably is related to the failure of the axons to regenerate and the misdirection of regenerating axons, which leads to inappropriate innervation of denervated muscles. Inappropriate innervation is thought to result in a loss in the ability to accurately recruit individual muscles and motor units within a muscle, resulting in the loss of motor control.

EXPLANATION: The initial radiographs show a comminuted displaced distal radius fracture, along with a displaced fracture of the base of the ulnar styloid. The displacement is best seen on the oblique view. After reduction and fixation of the radius, DRUJ stability should be assessed. The majority of scenarios that involve this injury pattern will not be unstable because of the oblique band of the interosseous ligament. When DRUJ instability is present after fixation of the radius, reduction and fixation of the ulnar styloid fracture is the best option to provide stability of the distal radioulnar joint (DRUJ). A study by Lawton and associates revealed that all distal radius fractures complicated by DRUJ instability were accompanied by an ulnar styloid fracture. A fracture at the ulnar styloid’s base and substantial displacement of an ulnar styloid fracture were found to increase risk for DRUJ instability. An ulnar styloid base fracture involves the insertion of the radioulnar ligaments and can cause DRUJ instability if displaced. If persistent instability is present after fixation of the ulnar styloid, DRUJ pinning is a reasonable option. Early ROM with splinting would not allow reduction or healing of the ulnar styloid and would result in persistent instability. Short-arm casting also would not allow stability of the DRUJ and would be a less reliable method with which to achieve healing of the ulnar styloid.

DISCUSSION: Enchondromas are the most common benign skeletal lesions identified in the bones of the hand. Most are incidentally found or initially become clinically evident after a pathologic fracture. If the patient has a fracture, the hand is immobilized until union. If the lesion is large and further pathologic fractures are expected, then an intralesional curettage and grafting procedure may be warranted. In this patient, the lesion has not significantly altered the size, shape, or morphology of the involved metacarpal head and recurrent fracture is unlikely. Observation with follow-up radiographs is considered appropriate management. REFERENCES: Campanacci M: Bone and Soft Tissue Tumors, ed 2. New York, NY, Springer-Verlag, 1999, pp 213-228. Marco RA, Gitelis S, Brebach GT, et al: Cartilage tumors: Evaluation and treatment. J Am Acad Orthop Surg 2000;8:292-304.

A recent review of 200 consecutive distal radius fractures noted that the overall incidence of extensor pollicis longus rupture was 3%. The causes are believed to be mechanical irritation, attrition, and vascular impairment. The fracture is usually nondisplaced and the patient notes weeks to months after injury the sudden, painless inability to extend the thumb. Treatment involves extensor indicis proprius tendon transfer or free palmaris longus tendon grafting.

DISCUSSION: The intraoperative radiograph reveals a scapholunate ligament disruption. Repair of the stout dorsal scapholunate interosseous ligaments is required. Interestingly, the results of scapholunate ligament injuries associated with distal radius fractures appear to be superior to those of isolated ligament injuries. REFERENCES: Smith DW, Henry MK: Comprehensive management of soft-tissue injuries associated with distal radius fractures. J ASSH 2002;3:153-164. Fernandez DL, Wolfe SW: Distal radius fractures, in Green DP, Hotchkiss RN, Pederson WC, et al (eds): Green’s Operative Hand Surgery, ed 5. Philadelphia, PA, Elsevier, 2005, p 693.

DISCUSSION: The patient sustained a growth plate fracture of the distal radius and ulna. Although treated with closed reduction and casting, the follow-up radiographs demonstrate shortening of the radius in comparison to the ulna, and the MRI scan confirms thinning of the distal radius growth plate and bony bars consistent with a growth arrest. At this time, the discrepancy in length is too minor to consider lengthening of the radius; in addition, excision of a physeal bar with minimal growth potential is not likely to restore the gross discrepancy. Ulnar styloid fractures are rarely symptomatic and do not require treatment in the asymptomatic patient. Closure of the distal ulna growth plate will prevent further discrepancy between the radius and ulna. REFERENCES: Vanheest A: Wrist deformities after fracture. Hand Clin 2006;22:113-120. Bae DS, Waters PM: Pediatric distal radius fractures and triangular fibrocartilage complex injuries. Hand Clin 2006;22:43-53.

The figures show a little finger to be incurving towards the ring finger (3a) and no flexion deformity (3b). This in itself is the definition of Clinodactyly. In addition to this curvature in the radioulnar/frontal plane, the deformity is one that affects the middle phalanx, usually bilateral, and autosomal dominant. Thedefinitions of the other distracters are self-explanatory (Staheli, Fundamental of Pediatric Orthopedics, 1998): Camptodactyly: non-painful flexion deformity of the PIP joint (i.e. AP Plane); abnormality of the insertions of the intrinsics and extrinsics flexor tendons; both hereditary and non-hereditary forms. Symbrachydactyly: digital absence in the form of transverse efficiency; teratogenic etiology resulting in absence distal metacarpals with finger nubbins. Kirner’s deformity: rare progressive deformity of the terminal phalanx of the small fingers with fingernails a curved and clubbed appearance; usually bilateral and appears during adolescence. Digiti minimi adductus: no such deformity found mention in the literature.

DISCUSSION: The line labeled 6 points to the A2 pulley. This structure is the condensation of the digital flexor tendon sheath corresponding to the proximal aspect of the proximal phalanx. Grayson’s ligament is volar to the digital nerve and artery. Cleland’s ligament is dorsal to the digital nerve and artery. The sagittal band anchors the extensor tendons over the metacarpophalangeal joints. The triangular ligament connects the lateral bands just proximal to the terminal tendon inserting onto the base of the distal phalanx. REFERENCES: Hollinshead WH: Anatomy for Surgeons: The Back and Limbs, ed 3. Philadelphia, PA, Harper and Row, 1982, p 467. Tubiana R, McCullough CJ, Masquelet AC: An Atlas of Surgical Exposures of the Upper Extremity. Philadelphia, PA, JB Lippincott, 1990, p 309.

In adults, the repair of high ulnar nerve injuries typically yields incomplete motor recovery and disappointing functional results despite early surgical intervention and careful surgical technique. Early transfer of the terminal branch of the AIN to the deep ulnar motor fascicle can rapidly reinnervate distal targets and potentially preserve motor end plate function in the intrinsic musculature of the hand because of the proximity of the nerve transfer to the target muscle. Sensory deficits due to an ulnar nerve injury can be restored through a transfer of median sensory fascicles to the distal ulnar sensory fascicles. This procedure typically would not be considered at the time of the original surgery, because sensory recovery is more likely than motor recovery in the setting of a high ulnar nerve injury. For radial nerve injuries, wrist extension can be restored through an FDS branch of the median nerve transfer to the ECRB branch of the radial nerve. The FCU fascicle of the ulnar nerve can be transferred to the biceps branch of the musculocutaneous nerve to restore elbow flexion and supination.

This patient has Lichtman stage 3B Kienböck disease. She is 55 years old and is a low-demand patient; however, she is a heavy smoker. Based on her condition and her current smoking status, salvage treatment that does not require bone healing such as a proximal row carpectomy is likely the best treatment option. A radial shortening osteotomy and a capitate shortening osteotomy may be helpful in offloading the lunate, but both procedures require bone healing and are better options in earlier stages of Kienböck disease. A scaphoid excision and four-corner fusion is typically performed for scapholunate advanced collapse or scaphoid nonunion advanced collapse wrist arthritis and would not be recommended in this scenario, as the lunate is avascular.

The thumb MCP ulnar collateral ligament (UCL) and index MCP radial collateral ligament (RCL) are the primary stabilizers to pinch. Secondary stabilizers include the volar plate, dorsal capsule, and accessory collateral ligaments. With insufficiency of either the thumb MCP UCL or the index MCP RCL, pinch strength will be severely weakened. The other options listed are unlikely to occur with this particular injury.

DISCUSSION: Intersection syndrome is also known as “squeakers wrist,” “oarsmen wrist,” and crossover tendinitis. It occurs where the first and second dorsal wrist compartment structures pass over one another, resulting in fibrosis, muscular changes, and inflammation of the bursa in this area. The structures involved are the abductor pollicis longus and extensor pollicis brevis (first dorsal compartment) that pass across the second compartment structures (extensor carpi radialis brevis and extensor carpi radialis longus).

The patient has a static deformity of the wrist with a fixed flexion deformity of more than 45°. Soft-tissue procedures such as those referenced in options A and B would not be sufficient to address the degree of contracture. Additionally, Botulinum toxin injections would not provide relief for capsular contractures. Wrist arthrodesis combined with a proximal row carpectomy has been shown to provide a functional and cosmetic alternative for patients with severe wrist flexion contractures.

EXPLANATION: The radioscaphocapitate ligament must be preserved in cases of proximal row carpectomy or scaphoidectomy with four-corner fusion. Failure to do so can result in ulnar translocation of the carpus. The attachment of the long radiolunate ligament to the lunate is compromised in proximal row carpectomy, although it is left intact in scaphoidectomy with four-corner fusion. Preservation of the dorsal radiocarpal ligament through a limited arthrotomy is advocated by Ozyurekoglu and Turker as a method of preserving the blood and nerve supply of the carpus, but this technique has not been proven to be required. The authors did cut through the dorsal intercarpal ligament in their exposure.